The present invention relates to high polymeric material compositions which are stabilized against photo-deterioration. More particularly the present invention relates to high polymeric material compositions, the photoresistance of which is improved by addition of a copolymer of 2-(2-hydroxy-3-allyl-5-substituted phenyl)benzotriazol compound with maleic acid or fumaric acid compound.
Synthetic polymers such as polyethylene, polypropylene, ABS resin, polyvinyl chloride and polyurethanes are subjected to degradation and discoloration upon exposure to ultraviolet light, with significant deterioration in mechanical strength.
Various kinds of light stabilizers have accordingly been proposed to inhibit such deterioration. Among the conventional stabilizers, 2-hydroxyphenyl-benzotriazols are known to impart a good photostability to the polymer, and therefore are widely used as light stabilizers.
And also, benzotriazols are known to absorb more ultraviolet rays than other absorbers do. Accordingly, benzotriazols are attempted to be used as a component of thermosetting resin, the resin is applied to the surface of the polymer, followed by heat curing, to protect the polymer against photo-oxidation.
However, the benzotriazols available are not entirely satisfactory in stabilizing effect since they are less compatible with the polymer, liable to escape from the polymer during the manufacturing process or heat curing or readily extracted with water or organic solvent, due to their low molecular weight and high crystallinity.
For this reason, Japanese Patent Publication No. 43-18395 provides polymers or copolymers of benzotriazols having acryloyl or methacryloyl group in their structure. These compounds, however, are also unsatisfactory since they are difficult to be manufactured and since they are readily subjected to elimination of benzotriazol molecules by hydrolysis.